1. Field of the Invention
The present invention relates to a novel design for a field emission device and a field emission display (FED) using the novel field emission device and a method of making the novel field emission device, the novel field emission device having improved focusing properties of an electron beam.
2. Description of the Related Art
Displays play an important role in information and media delivery and are widely used in personal computer monitors and television sets. Displays are usually either cathode ray tubes (CRTs), which use high speed thermal electron emission, and flat panel displays, which are rapidly developing. Types of flat panel displays include plasma display panels (PDPs), field emission displays (FEDs), liquid crystal displays (LCD) and others.
In FEDs, when a strong electric field is applied between a gate electrode and field emitters arranged at a predetermined distance on a cathode electrode, electrons are emitted from the field emitters and collide with fluorescent materials on the anode electrode, thus emitting visible light. FEDs are thin displays, at most several centimeters thick, having a wide viewing angle, low power consumption, and low production cost. Thus, FEDs together with PDPs attract attention as the next generation of displays.
FEDs have a similar physical operation principle to CRTs. That is, electrons are emitted from a cathode electrode and are accelerated toward and collide with an anode electrode. At the anode electrode, the electrons excite fluorescent material coated on the anode electrode to emit visible light. FEDs are different from CRTs in that the electron emitters are formed of cold cathode material. However, a problem with FEDs is limitations in the ability to focus the electron beam so that the each electron beam lands at a desired location on the fluorescent material to achieve good image quality.
To overcome this problem, U.S. Pat. No. 5,920,151 to Barton et al discloses a FED having an imbedded focusing structure. However, the focusing gate electrode in Barton ′151 is formed on an organic material called polyimide, which requires an outgassing process for discharging volatilized gas. Thus, such a FED cannot be applied to large displays. Therefore, what is needed is a design for an FED that provides improved electron focus and that can be applied to make large displays.